Hydroxy methionine analogs such as 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) are widely used as feed additives for livestock. HMTBA generally is manufactured as a dark liquid with a sulfurous odor containing at least about 88% HMTBA free acid, up to about 12% water, and about 0.5-3% of ammonium bisulfate, as well as other minor impurities. The chemical functionality of HMTBA makes it a suitable building block for many materials in many more applications and recently there has been a renewed interest in the use of HMTBA for specialty chemicals, such as polymers, surfactants, solvents, etc. All these specialty applications require well-defined specifications regarding color, odor, shelf life for the final product and, thus, for HMTBA as a component or raw material. Ammonium bisulfate while it is a known antibacterial agent or acidifier in feed contributes to undesired generation of color and odor in specialty chemical applications. Therefore, there is a need for thermally stable HMTBA formulations with minimal color and odor for specialty chemical uses.